AbstractThe behaviour of the smectic (surface stabilized ferroelectric liquid crystals – SSFLC) SmC* slab geometry «bookshelf» in an external DC electric field at the various angles to the smectic layers is considered. The stable states under applied field and the solutions for periodic boundary conditions were under our consideration. New stable states were obtained in the Dirichlet problem with periodic stripe-structures on the substrates. Commensurate and incommensurate domains were obtained for various wave numbers of periodic structures located on the top and bottom plates constraining SSFLC.